1. Field of the Invention
An embodiment of the present invention relates to a light-emitting element material, and a light-emitting element, a light-emitting device, an electronic device, and a lighting device including the material.
2. Description of the Related Art
In recent years, research and development have been extensively conducted on light-emitting elements. For example, in one of basic structures of light-emitting elements utilizing electroluminescence (EL), a layer containing a light-emitting substance is interposed between a pair of electrodes. By applying voltage to this element, light emission from the light-emitting substance can be obtained.
In order to improve element characteristics of such light-emitting elements, improvement of an element structure, development of a material, and the like have been extensively carried out (for example, Patent Document 1). For example, Patent Document 1 discloses a light-emitting element material including an organic compound capable of converting triplet excitation energy into light to achieve high-luminance emission or high emission efficiency.